title: Tumor necrosis factor receptor-associated factor (TRAF) 2 controls homeostasis of the colon to prevent spontaneous development of murine inflammatory bowel disease.
abstract: Fine-tuning of host cell responses to commensal bacteria plays a crucial role in maintaining homeostasis of the gut. Here, we show that tumor necrosis factor receptor-associated factor (Traf)2(-/-) mice spontaneously developed severe colitis and succumbed within 3 weeks after birth. Histological analysis revealed that apoptosis of colonic epithelial cells was enhanced, and B cells diffusely infiltrated into the submucosal layer of the colon of Traf2(-/-) mice. Expression of proinflammatory cytokines, including Tnfa, Il17a, and Ifng, was up-regulated, whereas expression of antimicrobial peptides was down-regulated in the colon of Traf2(-/-) mice. Moreover, a number of IL-17-producing helper T cells were increased in the colonic lamina propria of Traf2(-/-) mice. These cellular alterations resulted in drastic changes in the colonic microbiota of Traf2(-/-) mice compared with Traf2(+/+) mice. Treatment of Traf2(-/-) mice with antibiotics ameliorated colitis along with down-regulation of proinflammatory cytokines and prolonged survival, suggesting that the altered colonic microbiota might contribute to exacerbation of colitis. Finally, deletion of Tnfr1, but not Il17a, dramatically ameliorated colitis in Traf2(-/-) mice by preventing apoptosis of colonic epithelial cells, down-regulation of proinflammatory cytokines, and restoration of wild-type commensal bacteria. Together, TRAF2 plays a crucial role in controlling homeostasis of the colon.
authors.affiliation: Department of Immunology, Juntendo University School of Medicine, 2-1-1 Hongo, Tokyo 113-8421, Japan.
authors.forename: Jiang-Hu
authors.initials: JH
authors.lastname: Piao
authors.forename: Mizuho
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Beate
authors.initials: B
authors.lastname: Heissig
authors.forename: Koichi
authors.initials: K
authors.lastname: Hattori
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Takeda
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
authors.forename: Ko
authors.initials: K
authors.lastname: Okumura
authors.forename: Naohiro
authors.initials: N
authors.lastname: Inohara
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Nakano
mesh_terms: D000818:Animals; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D016207:Cytokines / Q000096:biosynthesis; D015536:Down-Regulation / Q000235:genetics; D006706:Homeostasis; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D047992:TNF Receptor-Associated Factor 2 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D016207:Cytokines; D047992:TNF Receptor-Associated Factor 2